This invention relates to a tissue sampling instrument, such as a forceps, employed in connection with a flexible fiberscope, and more particularly to such an instrument constructed to prevent the flexible control wire connected between the sampling device and the manipulating section from breaking and the forceps cup section at the end of the sampling device from being damaged, as by the application of violent or excessive operating force.
In the prior art tissue sampling instruments the operator grips the manipulating knob while simultaneously observing the internal body part or organ to be examined through a fiberscope or the like in order to properly direct or aim the instrument at the desired tissue or cells. In such a procedure the operator's attention is primarily occupied in observing the area under examination and in guiding the end of the instrument to the desired location, and he is thus liable to apply excessive force in manipulating or opening and closing the sampling device, which may lead to the breakage of the control wire or damage to the forceps sampling cup.
Further, in view of the curvature of the insertion path leading to the area to be examined the control wire must be relatively long in order to reach remote areas, and its length often changes with time and use. It is thus not practical to provide a stop mechanism to limit the movement of the operating knob to within a certain range to prevent wire breakage or damage.